Aqueous silicone dispersions containing hydroxylated polydiorganosiloxanes, colloidal silica and an organic amine or sodium hydroxide are described in U.S. Pat. No. 4,221,688 to Johnson et al. The dispersions are stable on storage in a pH range of from 9 to 11.5 and may be used after storing for at least 1 to 3 days.
U.S. Pat. No. 4,244,849 to Saam describes aqueous silicone dispersions which are obtained by adding an alkali metal silicate to an anionically stabilized aqueous emulsion of a polydiorganosiloxane having hydroxyl terminal groups. The dispersions prepared in accordance with the examples have pH values in the range of from 10.1 to 11.2.
It is an object of the present invention to provide aqueous silicone dispersions which may be used immediately after preparation without prolonged storage. Still another object of the present invention is to prepare aqueous silicone dispersions which are stable even in lower pH ranges, for example, around the neutral point. A further object of the present invention is to provide silicone-based aqueous coating systems and sealing compounds, which after evaporation of the water, cure on substrates to which they have been applied to form elastomeric coatings or sealing compounds that adhere well to substrates.